Languages understood in speech - pretty well: some dialects of English; if spoken slowly as if to a child - Mandarin, French, Italian, German, Yiddish.

Languages spoken: fluently, English only when drunk; as a child would - French; as a stupid child would - Italian, German, Yiddish; as a stupid foreign child would - Mandarin Chinese.

Languages written or understood in writing: a whole other set (mostly supplementary).